I just posted this video tutorial on Youtube: Fashion Watercolor tutorial for beginners. Hope you will like it. And here is the explanation, step by step. First of all, prepare your skin color. The skin color is made of orange-red, purple, a touch of blue, a touch of green, a little touch of white and water, as you consider it to be for your watercolor. If you want it softer, just add more water. It took me more than 40 seconds to match the colors and to combine them. You will learn to prepared the skin color by doing, and you will know when the right skin color is done. Until then, just try to match the colors until you get the result. Learn the exact intensity of the skin color and try to reproduce it and to combine those colors I mentioned, until you are satisfied.
Second, start painting the eyes. They are the most difficult part of your drawing. If the eyes are ok, there is a big chance for you to finish the drawing with great results. Start painting the eyes with the skin color and add more purple and blue and at the end, a little bit of black just to underline the shape of the eyes.
Paint with layers, start with the light shades and add more and more at the end. Go to the next level, the third: paint the lips and the nose shadow and let the eye area dry until the end, when you can add some contrast.
Fourth, add the background color and the hair. The background should help the painting to have a volume. It will help your portrait to appear closer, and sharper. The hair, you can learn how to do it in this tutorial on my Fashion teaching site.
Fifth and the last stage is to take a look at the image and add some contrast, details and improvements to your painting. Enjoy your art! Hope this helped you!